Print bar sensors

ABSTRACT

The present disclosure includes a description of an example print bar that includes an ejection die disposed on a support element, and a sensor disposed at a particular location on the support element.

BACKGROUND

Printing systems include devices and mechanisms, such as printheads andprint engines, for generating a printed image on print media. Suchsystems can also include devices and mechanisms for detecting andaligning the print media and for detecting or measuring printcharacteristics of the printed image on the print media.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a schematic representation of an example print bar.

FIG. 2 depicts a perspective view of an example printhead temperaturecompensation system.

FIG. 3 is a flowchart of an example method for printhead temperaturecompensation.

FIG. 4 example method for printhead temperature compensation.

DETAILED DESCRIPTION

Implementations of the present disclosure include print bars for use inprinting systems. Such print bars can include multiple inkjet dies, alsoreferred to herein as ejection dies, disposed across them for use inpage wide array printing systems. Accordingly, print bars describedherein can be used to print one or more printing materials along thefull width of a print media in a single pass.

To aid in the fast and efficient alignment and quality detection ofprinted images generated by such print bars, various examples includesensors disposed on the print bar that can detect various print mediapresence or orientation as well as print characteristics of the ejectiondies. In one implementation, the print bar can include multiple sensorsdisposed along the width of the print bar to help detect the printcharacteristics of regions printed by the ejection dies that haveoverlapping print nozzle arrays. In such implementations, the print barscan also include various devices or logic for controlling the ejectiondies and sensors. With the ejection dies and sensors disposed on theprint bar, a service station of the printing system in which the printbar is installed can service and/or clean excess or inadvertentlydeposited printing material from the surface of the ejection dies andthe sensors.

The print bar can also include various electronic connection elementsand mechanical connection elements by which the ejection dies and thesensors can be coupled to a controller in the printing system. Bysharing the electronic connection and the mechanical connections on theprint bar, the sensors can be included in the printing system withoutadditional connections or mounts. Similarly, by utilizing the servicestation already included in the printing device for cleaning theejection dies, the sensors can be cleaned without the addition of anadditional service station. In addition, the relative close orientationof the sensors and ejection dies on a single print bar provides for aless complex and less costly print media handler that maintains precisealignment in only one region of the printing system, such as the printzone. Such characteristics of the print bar described herein can helpreduce the cost and complexity of printing systems in which they areused.

FIG. 1 is schematic diagram of an example print bar 100-1 according tovarious implementations of the present disclosure. As shown, the printbar 100-1 can include multiple ejection dies 105. In the exampleillustrated, the print bar 100-1 includes N, where N is an integer,ejection dies 105. As such, the print bar 100-1 may include one ejectiondie (e.g., N=1). The ejection dies can include a corresponding array ofprint nozzles from which a coordinated pattern of the print materialdroplets can be ejected to form a printed image. The print nozzles caninclude various types of inkjet nozzles, such as piezoelectric inkjetnozzles and/or thermal inkjet nozzles. In some implementations, each oneof the ejection dies 105 can be formed using a correspondingmanufacturing process, such as a semiconductor manufacturing process,mechanical manufacturing process, optical manufacturing process and thelike.

In some implementations, the ejection dies 105 can be disposed andarranged along a dimension (e.g., length or width) of a support elementor housing of the print bar. The housing of the print bar can includevarious types of metals, plastics, composites, etc. In someimplementations, the housing of the print bar can been an injectedmolded part that includes reservoirs and channels for deliveringprinting material to the print nozzles in the ejection dies 105. Invarious implementations, the ejection dies 105 can be disposed on asupport element. The support element can be incorporated into thehousing of the print bar and be arrange along one of the dimensions ofthe print bar 100.

In implementations, the housing of the print bar 100 can include anover-molded plastic element in which the ejection dies 105 can bedisposed and held in place relative to one another and the othercomponents of the print bar 100-1. In one particular example, theover-molded part can be disposed around an arrangement of the ejectiondies 105 on a support element of the print bar and flowed to mold aroundthe dies. In such implementations, the print bar can also include asensor 110 disposed in the over-molded part. Accordingly, the ejectiondies 105 and the sensor 110 can be arranged and then disposed in theover-molded part of the housing of the print bar by flowing theover-molding material around the parts and a support element. Theorientation or arrangement of the sensor 110 and the ejection dies 105can depend on the dimensions of the ejection dies 105 and/or the sensor110. In related implementations, the orientation or arrangement of thesensor 110 and the ejection dies can depend on the dimensions of theprint bar 100, the printing device, or print engine in which the printbar 100-1 will be used.

The sensors 110 can include various imaging (e.g., digital camera) oroptical/photo detectors (e.g., photodiodes). The sensors 110 can beoperated to detect various conditions and operations of the printingsystem (e.g., a printer, a digital printing press, etc.) in which theprint bar 100 is included. For example, the sensor 110 can be operatedto sense the edges of print media, sense the location of printed blocksor lines used for the alignment of the ejection dies 105 and/or multipleprint bars 100, or sense the color and/or density of printed images forthe calibration of color or density performance of the ejection dies105.

In implementations of the present disclosure, a print bar 100 caninclude not only multiple ejection dies 105, but other electronic andmechanical components used to couple the print bar 100 to a printingdevice or system in which it is disposed. FIG. 2 depicts one exampleprint bar 100-2 that can include a sensor 110, electronic connectionelement 115, mechanical connection element 125, or interface/controlcomponent 135. The electronic connection element 115, mechanicalconnection element 125, or the interface/control component 135 can beintegrated into the print bar 100-2. In some implementations, thesubcomponents of the print bar 100-2 can be included in the moldingprocess or the over-molding process. The subcomponents, such as theelectronic connection element 115, mechanical connection element 125,the interface/control component 135 can be fixed in position relative tothe other components of the print bar 100-2 in the same over-moldingprocess used to arrange and fix the ejection dies 105-1 relative to thesensor 110.

As described herein, electronic connection element 125 can includevarious electrical connections for sending and receiving electronicsignals and electric power to and from the various subcomponents of theprint bar 100-2. For example, electronic connection element 115 caninclude terminals and connectors for receiving control signals from acontroller in the printing system in which the print bar 100-2 isdisposed for operating the ejection dies 105, the sensor 110, and/or theinterface/control component 135. Accordingly, any or all of thesubcomponents of the print bar 100-2 can make use of the electricalinputs and outputs provided by the electronic connection element 115 tocommunicate with other components of the printing system in which theprint bar is included. Use of the common electronic connection element115 can reduce the number of parts and cost associated with using aprint bar 100-2 in a printing system. In addition, if theinterface/control component 135 includes an application specificintegrated circuit (ASIC), then functionality or logic for operating thevarious subcomponents of the print bar 100-2, such as the sensor 110,and/or ejection dies 105, can be included in the ASIC. Similarly, whenused in combination with the appropriate logic or functionality includedin the interface/control component 135, the sensor 110 can be operatedto use the datum systems on the print bar 100-2 and/or the ejection dies105 f alignment of or sensor 110.

Mechanical connection element 125 can include various mechanicalregistration, alignment, locking, or structural elements for fasteningthe print bar 100-2 into the printing system in which it is disposed. Invarious examples, the mechanical connection element 125 can includemounting features (e.g., clips, latches, holds, stops, etc.) that matchof correspond to mounting features (e.g., clips, latches, holds, stops,etc.) in the printing system in which it is to be used. In addition,mechanical connection element 125 can include the housing and/or theover-molded element that maintains the relative physical orientation ofthe various subcomponents of the print bar 100-2.

FIG. 3 depicts another example print bar 100-3 which includes multiplesensors 110 and multiple ejection dies 105. While not shown in FIG. 3the print bar 100-3 can also include the electronic connection element115, mechanical connection element 125, or interface/control component135. In such implementations, the sensors 110 can be disposed in theover-molded portion of the print bar 100-3 in arrangements to detectprinted image characteristics associated with various individualejection dies 105 and/or groups of ejection dies 105. For example, thesensors 110 can be arranged across the print bar 100-3 in a positionparallel to the arrangement of a page wide array of ejection dies 105 toform a page wide sensor. Such page wide sensors can be used tocontinually or intermittently measure the alignment, color and/ordensity of the printed images generated by the ejection dies 105. Assuch, the sensors 110 can be used in combination to sense the variouspositional, alignments, or printing performance of the printing systemin which the print bar 100-3 is disposed in a zone corresponding to theprint zone in which the ejection dies 105 eject or deposit printingmaterial. Such an arrangement can allow for use of a single tightlyaligned print and color, density, or alignment feedback zone, instead ofa print zone, scanned zone, or user intervention to use a scanner in amulti-function or all-in-one device (e.g., a combination scan, print,fax, scan type device).

In some example implementations, the sensors 110 can be included atselected locations along a dimension of the print bar 100-3 to reducethe number of sensors 110 necessary. For example, a sensor 110 can bepositioned at the extreme ends of the array of ejection dies 105. Suchan arrangement can enable the print bar 100-3 to do alignmentmeasurements, similarly, the number of sensors 110 and be reduced in aprint bar 100-3 if there disposed in a location to detect the regions inwhich adjacent ejection dies 105 overlap to measure/detect color ordensity print characteristics in those regions.

FIG. 4 depicts a printing system 400 that includes a print bar 110according to various implementations of the present disclosure. Asshown, the printing system 400 can include the print bar 110, a printmedia handler 415, and the communication interface 430, each of whichcan be coupled to a controller 410. In the example shown in FIG. 4, theprint bar 110 can represent multiple print bars 110 (e.g., the printingsystem 400 can include multiple print bars 110).

In various example printing system is 400, the controller 410 caninclude functionality and/or logic for generating and receivingelectronic signals to and from the various other components of theprinting system 400. For example, the controller 410 can includefunctionality for sending and receiving signals to the print bar 110 tocontrol the operation of the various subcomponents of the print bar 110.As such, the control signals sent by the controller 410 to thesubcomponents of the print bar 110 can cause the ejection dies 105 twoeject printing material in a coordinated way to generate a printedimage. Similarly, the control signal sent by the controller 400 tend tothe subcomponents of the print bar 110 can cause sensor 110 to makevarious alignment, color, or density type measurements.

In various implementations described herein, the controller 210 can beimplemented as any combination of hardware and executable code. Forexample, the functionality of the controller 210 described herein can beimplemented as executable code executed in a processor of computersystem or other computing device.

The executable code, stored on a nonvolatile computer readable medium,can include instructions for operations that when executed by acontroller 210 causes the controller 210 to implement the functionalitydescribed in reference to the controller 210 and/or its subcomponents.Accordingly, controller 210 can be implemented in a system comprising aprocessor, a memory, a communication interface, and/or other digital oranalog logic circuits that can be used to store and/or executeoperations defined by executable code or code segments.

The processors of the system may be a microprocessor, amicro-controller, an application specific integrated circuit (ASIC), orthe like. According to an example implementation the processor is ahardware components, such as a circuit.

As described herein, any of the control signals sent by the controller400 tend to the print bar 100 can be handled by the electronicconnection element 115. The control of the functionality of the varioussubcomponents of the print bar 100 can also be handled by theinterface/control component 135 in response to a particular controlsignal sent by the controller 410. As such, various functionality of theprint bar 100 described herein can be implemented as any combination ofcomputer executable code or code segments and hardware distributedbetween the controller 410 and the interface/control component 135.

The print media handler 415 can also receive control signals that thecontroller 410 to pull, move, position, or align print media, such aspaper, card stock, film, or the like, relative to the print bar 100. Theprint media handler 415 can, for example, include various rollers,grabbers, conveyor belts, or servomotors. In such implementations, thecontroller 410 can use information received from the sensor 110 in theprint bar 100 as feedback to improve, calibrate or line the relativemotion of the elements of the print media handler 415. In someimplementations, the print media handler 415 can include or beassociated with a print bar service station they can include variouscomponents for cleaning or removing unintentionally deposited printingmaterial on the ejection dies 105 and/or the sensor 110. In suchimplementations in which the ejection dies 105 and sensors 110 aredisposed in the same print bar 100, the same service station can be usedfor cleaning both the ejection dies 105 and the sensors 110, thus,eliminating the inclusion of an individual service stations and/orcleaning protocols for the sensors 110 and/or the ejection dies 105individually.

The communication interface 430 can use the various communication mediaand protocols for sending and receiving electronic communication signalsor data between the printing system 400 and another computing device,such as a tablet computer, laptop computer, desktop computer, and thelike. As such, the communication interface 430 can include any type ofwired or wireless communication media or protocol for receiving printdata from which a printed image can be generated using the print bar 110or sending feedback data to another computing device to indicate thestatus of the printing system 400.

These and other variations, modifications, additions, and improvementsmay fall within the scope of the appended claims(s). As used in thedescription herein and throughout the claims that follow, “a”, “an”, and“the” includes plural references unless the context clearly dictatesotherwise. Also, as used in the description herein and throughout theclaims that follow, the meaning of “in” includes “in” and “on” unlessthe context clearly dictates otherwise. All of the features disclosed inthis specification (including any accompanying claims, abstract anddrawings), and/or all of the elements of any method or process sodisclosed, may be combined in any combination, except combinations whereat least some of such features and/or elements are mutually exclusive.

What is claimed is:
 1. A page wide print bar comprising: a plurality ofejection dies disposed along a longitudinal dimension of the page-wideprint bar on a support element; and a plurality of discrete sensorsdisposed at corresponding positions spaced from each other along thedimension of the support element, each sensor positioned to sense printcharacteristics of an image printed in an overlapping print zone on aprint media that corresponds to two adjacent ejection dies of theplurality of ejection dies.
 2. The page wide print bar of claim 1wherein at least some of the sensors each takes the form of an opticalsensor to detect a print characteristic of two of the ejection dies. 3.The page wide print bar of claim 1 wherein the support element comprisesan over-molded element.
 4. The page wide print bar of claim 1 furthercomprising an electrical connection element coupled to the ejection diesand the sensors.
 5. The page wide print bar of claim 4 furthercomprising a control component coupled to the ejection dies and thesensors.
 6. The page wide print bar of claim 1 further comprising amechanical connection element to couple the ejection dies and thesensors to a printing system.
 7. A printing system comprising: a printbar comprising: a plurality of ejection dies disposed across a dimensionof a support element; and a plurality of sensors disposed across thedimension of the support element to sense print characteristics of animage printed in a corresponding print zone; a print media handler toalign print media in the print zone; a controller to receive sensorsignals from the plurality of sensors and generate control signals tocontrol the plurality of ejection dies; and a shared service station toclean both the plurality of ejection dies and the plurality of sensors.8. The printing system of claim 7 wherein the plurality of sensors aredisposed at corresponding positions to sense the print characteristicsof the image deposited by two adjacent election dies in the plurality ofejection dies.
 9. The printing system of claim 8 wherein the positionscorrespond to regions in which the two adjacent ejection dies overlap.10. The printing system of claim 7 wherein the print bar furthercomprises an application specific integrated circuit (ASIC) comprisinglogic to control the plurality of ejection dies or the plurality ofsensors.
 11. The printing system of claim 7 wherein the print barcomprises a mechanical connection element corresponding to mountingfeatures in the printing system.
 12. The printing system of claim 7wherein the print bar further comprises an electronic connection elementcoupled to the plurality of ejection dies and the sensor and thecontroller.